1. Field of the Invention
The present invention is directed to a system and method for level shifting between a low voltage circuit and a high voltage circuit.
2. Background Art
Many integrated circuits are being manufactured that have reduced feature sizes and reduced core voltage levels (e.g., about 1–1.5V). These integrated circuits often drive higher voltage level circuits (e.g., operating at about 3–3.3V) at their output. Typically, a multi-stage level shifting device or circuit is positioned between the integrated circuit and the driven device. In this arrangement, one or more intermediate voltages (e.g., of about 2.5V) are required before the final voltage (e.g., about 3–3.3V) is produced. By requiring the intermediate voltage or voltages, the multi-stage level shifter is slowed by propagation delays and requires additional power for the additional level shifting stages. The increased circuit elements and additional required power supply increases the cost of the system. Also, by needing more stages for level shifting a larger overall circuit is required.
Therefore, what is needed is a one-stage level shifting device that allows for increased speed and efficiency during level shifting and reduced costs and size through reduced power requirements and reduced circuit elements.